Following the 1996 welfare reform, newly arrived older immigrants with less than 5 years of residence (NOIs) have been barred from Medicaid benefits. Neither are they eligible for Medicare due to lack of work history. This study examines the relationship between immigrant status (NOIs or not), health insurance, and health service use among older immigrants; whether insurance mediates the relationship between immigrant status and health service use. The 2000 National Health Interview Survey was analyzed. The sample includes respondents aged 65 or older who are foreign-born (N=1, 178). The adapted Andersen model was used. A series of logistic regressions show insurance is a complete mediator between immigrant status and health service use among older immigrants. Immigrant status was significantly related to the mediator, health insurance; older immigrants with longer than 5 years of residence were 31 times more likely than NOIs to have health insurance in terms of odds. Also, different from health service use among U.S.-born older adults, older immigrants' service use is significantly related to their insurance status. There was no direct relationship between immigrant status and health service use.